Distributer Cap Problems

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   So this year I ordered a new cap and rotor. The first time I start the engine I hear a loud ticking which I confused as Knocking. I freaked out and grabbed the camera to upload a video here for diagnosis. As I tried to identify the source of the knock, I out my hand in the distributer cap and felt a rhythmic vibration that was perfectly in sync with the knock. I pulled the cap and found the rotor was striking one of the posts in the replacement cap. you can see the cut in the metal of the post. 

Next I switched rotors back to the old one. Same result. 

Old rotor - new cap................Same result.

I was pretty sure I had a bad cap so I called SkiDim back and they sent me a new one (with a new gasket)  

Here are the results of the new(er) rotor and new cap. This time you can see that it's shaving the base of the posts down and creating metal fragments. Same result with all three rotors I have. 

I've never had a problem with any part of my distributer, cap, or rotor in ANY vehicle I 'have ever owned or worked on. The guy at SkiDim wants to think its a problem with my distributer saying it has play side to side when it's running. I don't agree seeing as the damage in both cases are different. 

Ideas? 

Chris

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Frankenotter Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: August-26-2012 Location: Milwaukee Status: Offline Points: 1072	Post Options Post Reply Quote Frankenotter Report Post Thanks(0) Quote Reply Topic: Distributer Cap Problems Posted: May-20-2016 at 4:19pm
	So this year I ordered a new cap and rotor. The first time I start the engine I hear a loud ticking which I confused as Knocking. I freaked out and grabbed the camera to upload a video here for diagnosis. As I tried to identify the source of the knock, I out my hand in the distributer cap and felt a rhythmic vibration that was perfectly in sync with the knock. I pulled the cap and found the rotor was striking one of the posts in the replacement cap. you can see the cut in the metal of the post. Next I switched rotors back to the old one. Same result. Old rotor - new cap................Same result. I was pretty sure I had a bad cap so I called SkiDim back and they sent me a new one (with a new gasket) Here are the results of the new(er) rotor and new cap. This time you can see that it's shaving the base of the posts down and creating metal fragments. Same result with all three rotors I have. I've never had a problem with any part of my distributer, cap, or rotor in ANY vehicle I 'have ever owned or worked on. The guy at SkiDim wants to think its a problem with my distributer saying it has play side to side when it's running. I don't agree seeing as the damage in both cases are different. Ideas? Chris
	1999 Ski Nautique 196

Mountain Man Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: May-09-2014 Location: Brevard, NC Status: Offline Points: 124	Post Options Post Reply Quote Mountain Man Report Post Thanks(0) Quote Reply Posted: May-20-2016 at 5:36pm
	You have a couple of options to verify if your distributor is worn. Remove the distributor cap and have someone turn the engine over - if extreme you may see the rotor wobble. A better method would be to remove the distributor from the engine, rigidly mount it, and set up a jig to hold a dial indicator, rotate the shaft at the gear and test for the lateral run-out of the center shaft assembly - where the rotor button attaches.

Frankenotter Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: August-26-2012 Location: Milwaukee Status: Offline Points: 1072	Post Options Post Reply Quote Frankenotter Report Post Thanks(0) Quote Reply Posted: May-20-2016 at 6:12pm
	Steve it may come to that, but if there were a lateral wobble of the rotor on the distributer, wouldn't cap #2 have lateral gouges like the first one? I would almost think the logical solution is they were sending me the wrong caps. However, that wouldn't account for the different wear patterns either. My last theory, is that the cap that I replaced this year (we'll call it cap zero), has a part number and a code starting with IMB 1008 and scalloped ridges on the roof of the cap. Neither of the replacement caps have the number nor the scallop pattern. Vince at Ski Dim says there's only one cap that has that seat pattern. I thrust the dudes at Ski Dim as they sell hundreds of these things per year, but something must be wrong. Maybe they changed the mold of the original cap? Did pretolight or Mallory merge recently? Chris
	1999 Ski Nautique 196

DrCC Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: April-12-2004 Location: at home Status: Offline Points: 2867	Post Options Post Reply Quote DrCC Report Post Thanks(0) Quote Reply Posted: May-20-2016 at 6:26pm
	What brand of cap ? It could be the wrong rotor. Whenever I get tune-up parts from O'Really, their mallory book has the wrong rotor listed for my YH Mallory.

Frankenotter Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: August-26-2012 Location: Milwaukee Status: Offline Points: 1072	Post Options Post Reply Quote Frankenotter Report Post Thanks(0) Quote Reply Posted: May-20-2016 at 6:43pm
	The package says "pcm".
	1999 Ski Nautique 196

Gary S Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096	Post Options Post Reply Quote Gary S Report Post Thanks(0) Quote Reply Posted: May-20-2016 at 10:47pm
	Is that a GT40 Chris? Post up a pic of the rotor please
	69 Mustang HM SS 95 Nautique Super Sport

Frankenotter Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: August-26-2012 Location: Milwaukee Status: Offline Points: 1072	Post Options Post Reply Quote Frankenotter Report Post Thanks(0) Quote Reply Posted: May-21-2016 at 1:54am
	It's not a GT 40. Just standard 351. I'll post a pic of the rotor when I get home Tuesday.
	1999 Ski Nautique 196

o00otii Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: March-21-2016 Location: Central Ca Status: Offline Points: 3	Post Options Post Reply Quote o00otii Report Post Thanks(0) Quote Reply Posted: May-28-2016 at 3:02am
	I recently did a tune up on my new to me 84 and noticed that the replacement cap from Skidim came with a thin fiber gasket, while the old one had a thicker rubber gasket. Not sure what the proper setup is but with just the thin gasket the cap was loose and sat too low for the rotor to contact the center of the cap contacts. It didn't seem right so I put on the thicker one. I'm aware there are a clip down and screw type caps. What did your cap come with? I'm curious to see what the issue ends up being as I'm new to these boats.

Distributer Cap Problems

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